AB1566 CRYOGLOBULIN TESTING IN A TERTIARY UNIVERSITY TEACHING HOSPITAL
Authors: P. Harkins, S. Cowley, A. Naughton, J. Dunne, N. Conlon, R. Conway
Journal: Annals of the Rheumatic Diseases (2023)

<h3>Background</h3> Cryoglobulinaemic vasculitis is a small vessel vasculitis that is typically associated with hepatitis C viral infection (80%), however, it can also be associated with lymphoproliferative disorders and autoimmune diseases. [1] It typically presents with rheumatological, cutaneous or renal manifestations, in addition to peripheral neuropathy. [1] It is associated with significant morbidity and mortality if left undiagnosed. The detection of cryoglobulins in serum is a prerequisite for diagnosis. However, testing methods are frequently influenced by artifact, resulting from ex-vivo cryoprecipitation. Therefore, samples are often unsuitable for analysis, resulting in diagnostic delay, with associated high health care cost, utility, and burden. <h3>Objectives</h3> To assess cryoglobulin testing at a large tertiary hospital in Dublin, Ireland. <h3>Methods</h3> A retrospective analysis was performed on all cryoglobulin tests ordered at a tertiary university affiliated hospital over a five-year period from January 2017 until December 2022. We collected baseline patient demographics, location from which sample was taken (outpatient versus inpatient), suitability of sample for analysis and results of processed samples. Appropriate statistical analysis was then performed. <h3>Results</h3> A total of 524 consecutive samples were sent for cryoglobulin testing over the five-year period. The mean age of patients undergoing testing was 53.29 (SD 17.40). There was a total number of 360 individual patients, of which 166 (46.1%) were females. 223 (43%) samples were unsuitable for analysis and were not processed accordingly. Of those samples not processed 114 (51%) were taken on an inpatient ward, whilst 109 (49%) were taken in the outpatient setting. Of the samples unsuitable for analysis, 209 (93.7%) were received at the incorrect temperature, 11(4.9%) were duplicate samples, 2 had an incorrect serum sample sent, and in one case no sample was received. Notably, of the samples deemed unsuitable for analysis, only 117 (52%) underwent repeat testing. Unexpectedly, there was no statistically significant association between sample suitability and gender, age, date or location of testing. <h3>Conclusion</h3> This study demonstrates the inability to process almost half of cryoglobulin test samples received at our institution. This undoubtedly results in significant diagnostic delay, in addition to unnecessary health care costs and utility. There is a crucial unmet need to increase education and awareness on optimal sample testing, in addition to the implementation of pathways to optimize sample collection and transportation. Finally, the failure to repeat unprocessed samples in a significant proportion of cases raises the question of initial indication for testing, and the need to review criterion for diagnostic testing. <h3>Reference</h3> [1]Kolopp-Sarda MN, Miossec P: <b>Cryoglobulinemic vasculitis: pathophysiological mechanisms and diagnosis</b>. <i>Current Opinion in Rheumatology</i> 2021, <b>33</b>(1):1-7. <h3>Acknowledgements:</h3> NIL. <h3>Disclosure of Interests</h3> Patricia Harkins Grant/research support from: Janssen Pharmaceuticals, Sharon Cowley: None declared, Aifric Naughton: None declared, Jean Dunne: None declared, Niall Conlon: None declared, Richard Conway: None declared.